Preparation of Intellingent Catalysts by Means of Layered Host Compounds Structurally Modified with Guest Molecules

合成了一种新型的主-客体催化剂（MMS），其中手性铑配合物以及结构调节的客体被插入蒙脱石中，并且观察到催化作用的剧烈变化取决于层间距以及客体分子的取向。具有不同层间距的多重改性催化剂（MMS）的制备：用结构调节客体如伯铵和季铵改性的蒙脱石（C_nH_<2n+2>NH_3^+（1-C_n），（C_nH_<2n+2>）_2（CH_3）_2NH_3^+（4-C_n），当n从10变化到18时，1 μ C_n和4 μ C_n的间隙间距（CS）分别为0.37 - 1.07 nm和1.93-2.88 nm。（2）通过改变主体的层电荷来控制客体分子的取向。（3）MMS对前手性烯烃和酮不对称加氢的催化作用：在30个大气压的H_2压力下，MMS催化剂对α-蒎烯和苯乙酮的加氢反应比相应的均相催化剂表现出更高的催化活性和选择性。这些结果表明MMS催化剂比均相催化剂更稳定。（4）层间距和客体取向对催化行为的影响：结果表明，在α-蒎烯加氢反应中，Rh-DIOP/C_nN^+/NaHT催化剂的层间距和客体分子的取向对催化活性和选择性有明显的影响。（CS=2.46-2.78nm）显示出1.3- 7.3%的转化率和50- 70%的低外消旋选择性，而Rh-DIOP/C_nN^+/LiTN（CS=1.93-2.88nm）显示出高于99.8%的转化率和92%的高外消旋选择性。由于LiTN的层电荷密度是NaHT的3倍，因此LiTN中的结构调节客体（C_nN^+）的取向几乎垂直于硅酸盐层，而NaHT中的取向在58 ~ 65度之间。特别是这些客体取向肯定会影响催化活性和选择性。

The novel host-guest catalysts (MMS), in which chiral rhodium complexes as well as structural tuning guests were intercalated into smectites, were synthesized, and drastic change in catalysis was observed depending on the interlayer spacing as well as the orientation of guest molecules.Preparation of multiple-modified catalysts (MMS) with various interlayer spacings : Smectites modified with structural tuning guests such as primary and quaternary ammoniums (C_nH_<2n+2>NH_3^+(1ﾟC_n), (C_nH_<2n+2>) _2 (CH_3)_2NH_3^+(4ﾟC_n), respectively) have clearance spaces (CS) of 0.37 -1.07 nm for 1ﾟC_n and 1.93-2.88 nm for 4ﾟC_n with changing n from 10 to 18. (2)Control of the orientation of the guest molecules by changing the layer charge of hosts. (3)Catalysis for the asymmetric hydrogenation of prochiral olefins and ketones by MMS : MMS catalysts show higher catalytic activity and selectivity than the corresponding homogeneous ones in the hydrogenation of alpha-pinene and acetophenones at 30 atm of H_2 pressure. These results indicate that MMS catalysts are more stable than the homogeneous ones. (4)Effect of the interlayer spacing and the guest orientation on the catalytic behavior : It is found that the interlayer spacing and the orientation of guests clearly affect the catalytic activity as well as the selectivity, In the hydrogenation of alpha-pinene, Rh-DIOP/C_nN^+/NaHT(CS=2.46-2.78nm) showed the conversions of 1.3-7.3 % with low exo-selectivity of 50-70 %, while Rh-DIOP/C_nN^+/LiTN(CS=1.93-2.88nm) showed much higher conversions over 99.8 % with high exo-selectivity of 92 %. Since LiTN has three times higher layer charge density than NaHT, the orientation of structural tuning guests (C_nN^+) in LiTN was nearly perpendicular to the silicate layer, while that in NaHT was in the range between 58 to 65 degree to the layer sheet. Particularly these guest orientations definitely affect the catalytic activity and selectivity.